New development composition for radiographic film

ABSTRACT

A photographic developer solution for manual processing of photographic (radiographic) film said solution comprising from about 10 to 30 grams per liter of hydroquinone, from about 0.3 to 0.9 grams per liter of phenidone, and further comprising a source of thiosulfate ion in an amount equivalent to from about 0.1 to 1.0 grams per liter of sodium thiosulfate.

United States Patent 1191 Versorese 1 Dec. 17, 1974 [54] NEW DEVELOPMENT COMPOSITION FOR 3,312,550 4/1967 Stewart et 111...... 96 66 HD RADIOGRAPHIC FILM 3,345,174 10/1967 Dotson et a1 96/50 R 3,431,108 3/1969 Willems 96/29 R [75] Inventor: Walfredo Versorese, Savona, Italy 3 5 7443 3/1971 DeHaes 96/29 R 3,615,512 10/1971 Ducrocq 96/29 R [73] Asslgnee Mmnesota Mmmg and 3,702,246 11/1972 Ohyama 96/29 R Manufacturing Company, St.Paul,

Minn.

[22] Filed: May 15, 1972 [21] Appl. No.: 253,428

[30] Foreign Application Priority Data May 15, 1971 Italy 50368/71 [52] U.S. Cl 96/66 R, 96/66.3, 96/66.4, 250/477 [51] Int. Cl G03c 5/30 [58] Field of Search 96/66 HD, 61 M, 48 PD, 96/29, 66; 250/320, 323, 477

[56] References Cited UNITED STATES PATENTS 2,751,300 6/1956 James et ul. 96/29 R 3,186,842 6/1965 DeHaes et a1 96/66 R OTHER PUBLICATIONS Mason, Photographic Chemistry, pp. l49151.

Primary ExaminerNorman G. Torchin Assistant Exami11er-M. F. Kelley Attorney, Agent, or Firm-Alexander, Sell, Steldt & DeLahunt 5 7] ABSTRACT A photographic developer solution for manual processing of photographic [radiographic] film said solution comprising from about 10 to 30 grams per liter of hydroquinone, from about 0.3 to 0.9 grams per liter of phenidone, and further comprising a source of thiosulfate ion in an amount equivalent to from about 0.1 to 1.0 grams per liter of sodium thiosulfate.

10 Claims, No Drawings The present invention relates to liquid photographic developer compositions and particularly to such compositions useful for developing radiographic films of the type designed for automatic machine processing.

Certain presently-available photographic films are designed for rapid (e.g., 90 seconds or less) machine processing. Such processing normally employs temperatures in the range of 35C, and utilizes speciallyformulated radiographic film characterized by containing a comparatively small quantity of silver (such as 9.0 grams per square meter) and by a comparatively high silver/gelatin ratio, which may often be higher than 1.2. Reduced quantities of gelatin permit rapid drying of radiographic film. Machine processing (e.g., machine development) involves passage of a film at relatively high temperatures between various rollers which knead and impregnate the film with developer liquid, permitting the film to develop acceptable maximum densities and contrasts, even when considering the relatively low quantities of silver in such machine-processable films.

Until now, however, machine-processable films (e.g., those characterized as above) have not provided completely satisfactory results when manually developed in the same solutions used for machine development. The reasons for this phenomenon are-believed to include the lower temperatures ordinarily used for manual development and the lack of thorough contact between liquid developer and radiographic emulsion which is available through machine processing. Accordingly, radiographic film producers have ordinarily prepared two types of radiographic films, one suitable for machine development and the other suitable for manual development.

It is an object of the present invention to provide a liquid photographic developer for manual development of machine-processable radiographic film.

It is another object of the invention to provide a method for manual development of machineprocessable photographic film.

Liquid developers normally employed in machine processing include hydroquinone and phenidone as developing agents, an antioxidant such as an alkali sulfite (e.g., sodium sulfite), a development inhibitor such as an alkali bromide, an alkalizing agent for raising pH, such alkali metal and ammonium hydroxides or sodium carbonate, etc., a pH controlling agent such as an alkali metal metaborate or tetraborate, and an organic foginhibiting agent such as benzotriazole, S-methylbenzotriazole, 6-nitro-benzimidazole and l-phenyl-- mercaptotetrazole, etc. Such compositions ordinarily also include an anticalcium substance such as an alkali polyphosphate, or alkali salts of the ethylenediaminotetraacetic acid type. Such developers can be, if de-, sired, marketed as concentrated liquids to be diluted prior to use, for example, in a one-fourth or one-fifth ratio. For ease of packaging, liquid developer components can be divided into several, separately packaged portions. For example, in one instance it may be desirable to divide the liquid developer into two concentrated portions, one acidic in nature and the other basic in nature. Such portions, when mixed and diluted, will provide a developing solution ready for use (working solution). The portion which is basic in nature will have a pH normally higher than the intended working solution, and may tolerate a high concentration of hydroquinone-if desired. Phenidone can be included in the alkaline portion, in the acid portion, or can be divided between the two portions.

Various other liquid developer components as mentioned above may be distributed between the concentrated portions as desired. For example,-the basic portion may include the pH control agent and antioxidant, whereas the acid portion may may include the develop ment inhibitor and fog inhibitor. it will be understood that the developer of the invention, and the various concentrated portions as mentioned above, are aqueous in nature.

The hydroquinone and phenidone components of the above-described liquid photographic developers are ordinarily used within concentration limits known to the art. Preferably, hydroquinone is employed in amounts ranging from about 10 to about 30 grams per liter, and phenidone is employed in amounts ranging from about 0.3.to about 0.9 grams per liter. The pH of such liquid developers is ordinarily in the range of from about 10 to about 11 (preferably 10.2 to 10.5), and may be regulated by use of an alkalizing agent.

According to the present invention, it has been found that the hydroquinone/phenidone liquid developer compositions of the type hereinabovedescribed may be modified so as to permit excellent results to be obtained in manual development of machineprocessable radiographic films. The modification comprises incorporating into such liquid developers a source of thiosulfate ions in an amount-equivalent, in thiosulfate ions, to from about 0.1 to about 1.0 grams per liter of sodium thiosulfate.

Thus, briefly, the present invention relates to a liquid photographic developer having a pH of from about 10 to about 1 1 (preferably from about 10.2 to about 10.5) and comprising from about 10 to about 30 grams per liter of hydroquinone and about 0.3 to about 0.9 grams per liter of phenidone, the developer being characterized by including a source of thiosulfate ions in an amount equivalent, in thiosulfate ions, to from about 0.1 to about 1.0 grams per liter of sodium thiosulfate.

In an effort to improve the manual development characteristics of machine-processable radiographic films developed with known liquid photographic developers of the hydroquinone/phenidone type, various substances of the thiourea, sodium thiosulfate, and potassium sulfocyanate type have been added to the developer. These are substances which conform soluble complexes with silver ions or can originate salts with solubility products higher than the solubility product of the silver halide present in the radiographic emulsion, or can free ions whichwill complex silver ions as watersoluble complex salts. Such substances, however, have not been found to yield beneficial results. Surprisingly, it has been found according to the present invention that the addition of a source of thiosulfate, such as sodium or ammonium thiosulfate, in an amount equivalent, in thiosulfate ion, to sodium thiosulfate in an amount of from 0.1 to 1 gram per liter of working solution, yields unusually good results when the resulting working solution is employed for manual development of a machine-processable radiographic film. This is a unique result in view of the fact that the resulting solutions do not show a beneficial improvement when employed in machine processing of machine-processable radiographic films.

The liquid photographic developers of the present invention may, of course, Contain the various developer additives as previously exemplified, and may be packaged as concentrates as exemplified above. The optimum amount of thiosulfate which is added to hydroquinone/phenidone liquid developers to form the developers of the invention may vary according to the type of developer which is used and the type of radiographic material which is developed, and this amount can be easily determined by the skilled artisan. it has been found, however, that the amount of the source of thiosulfate ions can vary only within certain predetermined limits; these limits corresponding to thiosulfate ions in an amount equivalent to from about 0.1 to about 1.0 grams of sodium thiosulfate per liter of working solution.

The invention may be more easily understoodby reference to the following illustrative, non-limiting examples.

EXAMPLE 1 A medical radiographic film, suitable for rapid machine processing (Minnesota Mining and Manufacturing Company Medical X-Ray film type R) comprising a silver bromoiodide emulsion with about 9 g of silver per square meter and a silver/gelatin ratio of 1.80 was radiographically exposed and then divided into three portions.

The first portion was processed by machine using a processing cycle of 90 seconds at 33C (a Kodak X- OMAT M6-RP X-Ray Processor) comprising as development solution the Kodak RP Medical X-OMAT Deve1oper-Replenisher type MX 810. The second portion was processed in a manual processing cycle of 3.5 at 20C using a development bath obtained by dilution of a concentrated liquid development composition consisting of two parts, A and B with the following relative composition:

The working" development solution (solution C) was obtained by dilution of 250 cc of part A with 750 cc of common water and adding 20 cc of part B in order to obtain a final pH of 10.35.

The third part of the film was processed in a manual processing cycle of 3.5, wholly equivalent to the pre- 4 ceding cycle, except that the processing bath included sodium thiosulfate present in part A of the concentrated liquid development composition in amount of The results obtained are given in the following table.

TABLE 1 Fog Relative Average Maximum Sensitivity Contrast Density Part 1 0.22 7.8 2.64 3.39 Part 2 0.20 6.5 2.30 2.50 Part 3 0.20 7.0 2.60 3.22

EXAMPLE 2 Samples of various radiographic films (Radio Medica Type N, Radio lndustriale Gamma and Radio Industriale Lambda, all of 3M Company) having emulsions with concentrations of silver per square meter of 9, 10, 9.7, and 24 g, respectively, and having respective silver/gelatin ratios of 1.80, 0.63, 0.4, and 1.00, were exposed radiographically, and then cut into several strips. Each of these strips was processed in a manual processing cycle of 3.5 at 20C employing various types of development baths, wholly analogous to the solution C of Example 1. Each development bath was either devoid of other additives or included sodium thiosulfate, sulfocyanate and thiourea m the amounts indicated in the following table.

TABLE 2 Relative Fog Average Sensi- Maximum Contrast tivity Density Radio T R No addition 0.20 1.75 12.30 2.50 Addition of Na s o, 0.10 g/liter 0.20 1.90 13.00 2.60 0.25 g/liter 0.20 2.10 13.80 2.77 0.50 g/liter 0.20 2.15 13.90 2.98 1.01 g/liter 0.20 1.75 13.80 3.00 2.02 g/liter 0.20 1.50 13.00 2.83 Radio T N No addition 0.22 2.10 12.40 3.66 Addition of Na s o 0.25 g/liter 0.22 1.95 12.70 3.66 0.50 g/liter 0.23 2.05 13.20 3.69 1.01 g/liter 0.23 1.90 13.90 3.74 2.02 g/liter 0.24 1.80 14.40 3.74 Radio T Gamma No Edition 0.23 1.60 7.80 4.00 Addition of Na S,O;, 0.25 g/liter 0.23 1.90 8.85 400 0.50 g/liter 0.24 1.80 900 400 1 01 g/liter 0.30 1.95 10.20 400 2.02 glliter 0.30 1.75 1 1.30 4.00 Radio T Lambda No addition 029 2.45 8.00 400 Addition of M 5 0. 0.25 glliter 0.26 2.10 7.80 4.00 0.50 g/liter 0.24 1.95 850 400 1.01 g/liter 0.24 1.50 8.95 4.00 2.02 g/liter 0.31 1.40 9.00 4.00 Radio T R No Edition 0.19 1.65 13.60 2.54 Addition of KCNS 0.10 g/liter 0.19 1.65 13.40 2.54 0.25 glliter 0.19 1.70 13.25 2.54 0.50 g/liter 0.19 1.75 13.40 2.58 1.01 g/liter 0.20 1.75 13.50 2.64 2.02 g/liter 0.20 1.65 14.50 2.73 Radio T N No Edition 0.22 2.05 12.80 3.77 Addition of KCNS 0.25 g/liter 0.22 2.10 11.15 3.76 0.50 g/liter 0.23 2.10 13.40 3.78 1.01 g/liter 0.22 1.90 13.50 3.80

TABLE 2-Continued Relative Fog Average Sensi- Maximum Contrast tivity Density [02 g/liter 0.23 2.10 13.80 3.76 Radio T Gamma No addition 022 1 .50 10.00 4.00 Addition of KCNS 0.25 glliter 0.23 l.50 9.70 4.00 0.50 glliter 0.24 l.50 9.90 400 101 glliter 0.26 1.50 11.20 400 202 g/liter 0.36 l.50 18.00 400 Radio Tm Lambda No addition 023 2.50 7.80 4.00 Addition of KCNS 0.25 g/liter 0.24 2.70 7.80 4.00 0.50 g/liter 0.26 2.90 8.25 4.00 1.01 g/liter 0.28 2.80 8.25 400 2.02 g/liter 0.28 2.50 8.75 400 Radio T e R No addition 0.20 1.55 13.20 2.58 Addition of Thio urea 0.25 g/liter 0.78 1 50 10.25 2.72 Radio T e N No addition 0.23 2.10 12.15 2.74 Addition of Thiourea 0.25 g/liter 0.34 1.95 10.75 3.30 Radio T e Gamma No addition 0.22 1.50 9.75 400 Addition of Thio- Urea 0.25 g/liter 2.84 l.50 6.20 4.00 Radio T e Lambda No addition 0.24 l.50 10.00 4.00 Addition of Thiourea 0.25 g/liter 1.70 3.10 5.50 400 EXAMPLE 3 A material for medical radiography, of the type suitable for rapid machine development (Kodak Medical X-Ray Film RP X-OMAT Rapid Processing) was radiographically exposed, then divided into two parts. The first part was processed by machine in Kodak X-OMAT M6-RP X-Ray Processor in a processing cycle of 90 seconds-employing the development bath Kodak RP Medical X-OMAT Developer-Replenisher Type MX810 of Eastman Koda. The second part was processed in a manual processing cycle comprising'a development bath wholly analogous to solution C of Example l but containing, according to the present invention, 0.5050 g of sodium thiosulfate per liter of solution.

The results are indicated in the-following table.

What is claimed is:

l. A liquid photographic developer having a pH of from about 10 to about 1 l and comprising about 10 to about 30 grams per liter of hydroquinone and from about 0.3 to about 0.9 grams per liter of phenidone, said developer further comprising a source of thiosulfate ions in an amount equivalent, in thiosulfate ion, to from about 0.1 to about 1.0 grams per liter of sodium thiosulfate.

2. The liquid photographic developer of claim 1 wherein said thiosulfate ion source is an alkali metal or ammonium thiosulfate.

3. The liquid photographic developer of claim 1 wherein said source of thiosulfate ions is sodium thiovsulfate or ammonium thiosulfate.

4. The liquid photographic developer of claim 3 wherein said source of thiosulfate ions is present in an amount corresponding, in thiosulfate ion, to from about 0.3 to about 0.6 grams per liter.

5. The liquid photographic developer according to claim 1 wherein the pH of said developer is from about 10.2 to about 10.5.

6. A method for the manual development of a machine processable photographic film which comprises manually treating said film in a liquid photographic developer having a pH of from about 10.0 to about 1 1.0 and comprising from about 10 to about 30 grams per liter of hydroquinone, from about 0.3 to about 0.9

grams per liter of phenidone, and a source of thiosulfate ions in an amount equivalent, in thiosulfate ion, to

sodium thiosulfate in an amount ranging from about,

0.1 to about 1.0 grams per liter.

7. The method according to claim 6 wherein said liquid photographic developer contains ammonium thiosulfate or sodium thiosulfate as said source of thiosulfate ion.

8. The method according to claim 6 wherein said source of thiosulfate ions is present in an amount equivalent, in thiosulfate ion, to from about 0.3 to about 0.6 grams per liter of sodium thiosulfate.

9. The method according to claim 6 wherein the pH of said liquid photographic developer ranges from about 10.2 to about 10.5.

10. The method according to claim 6 wherein the photographic film is radiographic film. 

1. A LIQUID PHOTOGRAPHIC DEVELOPER HAVING A PH OF FROM ABOUT 10 TO ABOUT 11 AND COMPRISING ABOUT 10 TO ABOUT 30 GRAMS PER LITER OF HYDROQUINONE AND FROM ABOUT 0.3 TO ABOUT 0.9 GRAMS PER LITER OF PHENIDONE, SAID DEVELOPER FURTHER COMPRISING A SOURCE OF THIOSULFATE IONS IN AN AMOUNT EQUIVALEN, IN THIOSULFATE ION, TO FROM ABOUT 0.1 TO ABOUT 1.0 GRAMS PER LITER OF SODIUM THIOSULFATE.
 2. The liquid photographic developer of claim 1 wherein said thiosulfate ion source is an alkali metal or ammonium thiosulfate.
 3. The liquid photographic developer of claim 1 wherein said source of thiosulfate ions is sodium thiosulfate or ammonium thiosulfate.
 4. The liquid photographic developer of claim 3 wherein said source of thiosulfate ions is present in an amount corresponding, in thiosulfate ion, to from about 0.3 to about 0.6 grams per liter.
 5. The liquid photographic developer according to claim 1 wherein the pH of said developer is from about 10.2 to about 10.5.
 6. A method for the manual development of a machine processable photographic film which comprises manually treating said film in a liquid photographic developer having a pH of from about 10.0 to about 11.0 and comprising from about 10 to about 30 grams per liter of hydroquinone, from about 0.3 to about 0.9 grams per liter of phenidone, and a source of thiosulfate ions in an amount equivalent, in thiosulfate ion, to sodium thiosulfate in an amount ranging from about 0.1 to about 1.0 grams per liter.
 7. The method according to claim 6 wherein said liquid photographic developer contains ammonium thiosulfate or sodium thiosulfate as said source of thiosulfate ion.
 8. The method according to claim 6 wherein said source of thiosulfate ions is present in an amount equivalent, in thiosulfate ion, to from about 0.3 to about 0.6 grams per liter of sodium thiosulfate.
 9. The method according to claim 6 wherein the pH of said liquid photographic developer ranges from about 10.2 to about 10.5.
 10. The method according to claim 6 wherein the photographic film is radiographic film. 